8-Week Weight Loss: Foods to Cut for Results

Many people try to maintain a healthy diet, go for walks or exercise regularly – and yet they still don’t see results on the scales. The weight remains constant, the energy decreases and the motivation dwindles. A current study from the USA now provides a possible explanation: apparently it is not the amount of food that is important, but rather the degree to which it is processed.

According to American scientists, highly processed foods can have a noticeable effect on metabolism – even if the diet appears healthy at first glance. Even small changes in everyday life, such as when shopping or cooking, could therefore be more effective than strict diet programs.

The degree of processing has a direct influence on metabolism

The study was conducted at South Dakota State University. Over several months, the scientists followed 36 older adults who were on average 72 years old and slightly overweight. The aim was to investigate the effects of the degree of processing of food on weight, metabolism and hormonal balance.

The test subjects were divided into two groups with different nutritional plans:

• One group consumed lean pork daily as their main source of protein.
• The other group had a vegetarian diet with legumes such as lentils and beans.

Both diets met the official US dietary guidelines. The meals were freshly prepared, without additives, flavor enhancers or ready-made sauces. As a result, the proportion of industrially processed foods in the daily energy intake fell from around 50 percent to just 13 percent. After just a few weeks, a clear effect was noticeable: the participants automatically consumed fewer calories – even though the amount of energy offered remained the same.

Less hunger, more energy – and a reduction in belly fat

On average, the participants reduced their daily calorie intake by around 400 kilocalories. After eight weeks, they had lost an average of four kilograms – without any strict diet restrictions or feeling hungry. What was particularly noticeable was the decrease in abdominal fat, which fell by an average of 13 percent.

Important metabolic values also improved significantly:

• Insulin levels fell by about 20 percent
• Insulin sensitivity increased by around 25 percent
• LDL cholesterol reduced by 10 to 12 milligrams per deciliter (about 0.26-0.31 mmol/L)
• Inflammatory markers such as CRP decreased significantly

These positive changes were equally noted in both groups. Study leader Professor Moul Dey emphasizes: “Two diets, one with meat, one vegetarian, led to the same results. What was crucial was how heavily the food was processed.”

Fresh foods affect hormones

The participants’ hormone levels also changed significantly. The hormone FGF21, which is responsible for regulating energy balance, increased by up to 50 percent. At the same time, leptin levels, which control appetite, fell by about two nanograms per milliliter.

“Our data demonstrates for the first time coordinated changes in these two hormones in older people due to a low-processed diet,” says Dey. This combination suggests that the body uses energy more efficiently when meals consist of natural ingredients.

In addition, total cholesterol fell by 20 to 25 milligrams per deciliter and LDL cholesterol by up to 12 milligrams per deciliter. This led to an improvement in cardiovascular profile – an important factor for older people who often face multiple health risks.

Fresh food instead of a strict diet

What is particularly noteworthy is that the participants were able to adhere to the nutritional plans without any difficulties. There was no need to count calories or do any complicated planning. “They simply replaced ready-made products with freshly prepared meals,” explained Saba Vaezi, a doctoral student on the research team.

The weight loss was evenly distributed: it affected not only the abdominal area, but also the hips and thighs. This suggests that the entire metabolism is positively influenced.

• Fresh preparation automatically reduces calorie intake.
• Fiber from vegetables and legumes ensures a longer-lasting feeling of satiety.
• A lower proportion of fat and sugar relieves insulin and blood lipid levels.

Long-term weight loss remains challenging

However, one year after the study was completed, there was a relapse: many participants returned to their original eating habits. The proportion of highly processed foods rose again to around 44 percent – almost as high as before the study began. Some of the positive effects were lost as a result.

From this we can conclude: A long-term reduction in industrially processed products can help to permanently stabilize weight as well as insulin and cholesterol levels. “Less processed ingredients are enough to bring the metabolism back into balance,” emphasizes Dey.

Briefly summarized:

• The level of processing of food has a greater impact on weight and metabolism than the amount of calories consumed.
• By avoiding highly processed products, you automatically consume less energy, can lose weight more easily and reduce belly fat – without a strict diet or starvation.
• A diet full of fresh and simply prepared foods has been proven to improve insulin levels, blood lipid levels and inflammatory markers.

By the way: The right size also plays a crucial role during pregnancy. Previous guidelines on weight gain are now considered outdated – and, according to the WHO, could even pose risks. You can find out more about this in our article.